名媛直播

Disclaimer: I am a newbie and don't know jack squat about bonsai.

I would like to make a bonsai out of a Japanese maple, which is about 12' tall. From what I can gather in reading and watching videos, I MAY need to cut the main leader/trunk/line (see attached).. I came to this potential conclusion based on watching a Herons 名媛直播 video on YT where all of his maples had this main line cut (see photo). While he doesn't say in the video, I assume this prevents the tree from growing up.

Welcome and good luck.

Do keep in mind you will need to layer it off the rootstock as the grafting site will only get urglier over time.

^ sorry I don't understand what you mean?

kigiin wrote: ^ sorry I don't understand what you mean?

which means that you are not ready to do something as drastic as "cutting the main leader/trunk/line"

Your tree is grafted. The roots of the tree are a different species than the top. The graft is clearly visible - there where the trunk changes color.
This graft will get uglier over the years. You'd need to airlayer it.

I am told by a local arborist that all Japanese Maples that are not of the original variety are grafted. I am not sure this makes sense to me but he was adamant about it so what do I know! He went on to say the grafted area would not be a problem. Maybe he is a good arborists but a not so good bonsai disciple. .

That is not entierly correct.

If you have a maple varity, the seed plant will not be the same varity. There are two ways to propagate the same varity. That is grafting or air/soil layering.

In my local garden center, most of the plants is layered but sometimes i see grafted ones.

Br
Magnus

It is not true. Many varieties are grown from cuttings. It is more certain to do grafting than taking cuttings so for commercial purpose grafting is often used. ALso, the wild version has strong roots and is more forgiving for bad soil.

But many grow fine once on their own roots certainly in bonsai culture where we have much more control.

In bonsai the grafting transition is considered unwanted.

Thank you

It is correct that most of the varieties of Japanese maple are grafted. There are countless varieties and many are not so strong on their own roots.
There are quite a few that do well without having to be grafted.

I happen to have 5 different varieties of maples.
None of them grafted, all from cuttings or air layers.
The kotohime, for instance, struggles in the summer and it is a slow grower, but... In my opinion patience pays off and better slow than grafted.
Others disagree, of course, and thai is fine also.